Efficient Synthesis of β-Hydroxy Sulfides and β-Hydroxy Sulfoxides Catalyzed by Cu/MgO Under Solvent-Free Conditions

Regio-, stereo-, and chemoselective ring opening of epoxides with thiols using Cu/MgO as a heterogeneous catalyst has efficiently been carried out to produce the corresponding β-hydroxy sulfides in excellent yields at room temperature under solvent-free conditions. The treatment of the epoxides with thiols and 50% aqueous H₂O₂ in the presence of the same catalyst at room temperature affords the β-hydroxy sulfoxides in excellent yields.     

Tartaric Acid–Catalyzed Synthesis of α-Aminophosphonates Under Solvent-Free Conditions

A facile procedure is developed for the synthesis of α-aminophosphonates, using tartaric acid as a stable, environmentally benign, low cost, and easily available organocatalyst. In the presence of tartaric acid (10 mol%), triethyl phosphite reacts with imines (generated in situ from an aldehyde and an amine) to yield the corresponding α-aminophosphonates. The organocatalyst tartaric acid is more stable during reaction. The catalyst provides easier workup, affords better yields, and takes less reaction time in comparison to generally used Lewis acid catalysts.

CAN Catalyzed Preparation of β-Enamino Ketones from Amines and Acetylacetone

The enamino ketone moiety has attracted much interest because it is a basic and versatile structure for organic synthesis. A number of reviews have been published about the chemistry of β-enamino ketones1-3. It is therefore not surprising that many synth…     

Erlenmeyer Synthesis for Azlactones Catalyzed by Ytterbium(III) Triflate under Solvent‐Free Conditions

A series of 4‐arylidene‐2‐phenyl‐5(4)‐oxazolones were synthesized from cyclodehydration–condensation of hippuric acid, aromatic aldehydes, and acetic anhydride catalyzed by ytterbium(III) triflate under mild conditions in excellent yields.     

Silica Chloride–Catalyzed Synthesis of Thiiranes from Oxiranes Under Solvent-Free Conditions

A mild, simple, and efficient method for the synthesis of thiiranes from epoxides using a catalytic amount of silica chloride under solvent-free conditions has been developed. Experimental simplicity, simple work-up procedure, and solvent-free reaction conditions are important features of the present protocol.     

Scandium(III) Triflate–Catalyzed Coumarin Synthesis

Scandium(III) triflate is an excellent catalyst in the von Pechmann condensation. The solvent-free catalytic reactions proceed smoothly with a range of phenols and β-ketoesters in the presence of 10 mol% scandium(III) triflate at 80 °C. This simple method affords various 4-substituted coumarins in good to excellent yield and is superior to the classical method in several aspects: solvent-free conditions, short reaction times, a decreased catalyst loading, a mild reaction temperature, and an easy workup.     

Ammonium Chloride–Catalyzed One-Pot Synthesis of 4(3H)-Quinazolinones Under Solvent-Free Conditions

Ammonium chloride, which is a very inexpensive and readily available reagent, can efficiently catalyze three-component, one-pot condensation reactions of 2-amino-benzoic acid esters, ortho esters, and aromatic amines to afford the corresponding 4(3H)-quinazolinones in good to excellent yields under solvent-free conditions.     

One-Pot Tandem Synthesis of β-Trimethylsilyloxy Thioesters from Thioacids,Epoxides, and HMDS Catalyzed by Silica Gel Under Solvent-Free Conditions

A procedure for one-pot preparation of β-trimethylsilyloxy thioesters from epoxides, thioacids, and hexamethyl disilazane (HMDS) in the presence of silica gel under solvent-free condition was developed. The desired silylated products were isolated in good to excellent yields after silica-gel column chromatography.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

An Efficient and Novel Method for the Synthesis of β-Aroylpropionic Acids Under Solvent-Free Conditions

Abstract

A simple and rapid reaction of succinic anhydride with aromatic hydrocarbons is described. The reaction is conducted under Friedel–Crafts conditions in the absence of solvent at room temperature using aluminium chloride as catalyst.     

Montmorillonite K10–Catalyzed Michael Addition of Indoles to Nitroolefins Under Solvent-Free Conditions

Montmorillonite K10 is a very inexpensive and readily available reagent and efficiently catalyzes the Michael addition of indoles to nitroolefins under solvent-free conditions. Reasonable to excellent yields of the desired products were obtained in most cases.     

OH−/Silica-Mediated One-Pot Synthesis of Dithiocarbamates Under Solvent-Free Conditions

Abstract

An efficient, versatile, and environmentally benign method for the synthesis of dithiocarbamates under solvent-free conditions is reported. The Michael addition of electron-deficient alkenes with alkyl or aryl amines and CS₂ in the presence of OH^?/silica in a one-pot three-component reaction protocol gave the corresponding dithiocarbamates in good to excellent yields. This method is suitable for a wide range of amines and a variety of Michael acceptors in solvent-free conditions. The results of the present work show the desired products in excellent yields.     

Efficient One-Pot Condensation of β-Naphthol,Aldehydes, and Cyclic 1,3-Dicarbonyl Compounds Catalyzed by p-TSA Under Solvent-Free and Sonication Conditions

A facile and efficient procedure has been developed by one-pot condensation of β-naphthol, aldehydes, and cyclic 1,3-dicarbonyl compounds for the synthesis of 8,9,10,12-tetrahydrobenzo[a]xanthen-11-one or 8,9-dihydrobenzo-[f]cyclopenta[b]chromen-10(11H)-one derivatives catalyzed by p-toluenesulfonic acid under solvent-free and sonication conditions.     

Mild and Convenient Synthesis of 1,2‐Dihydroquinolines from Anilines and Acetone Catalyzed by Ytterbium(III) Triflate in Ionic Liquids

A mild, convenient, and efficient process has been developed for the synthesis of 2,2,4‐trimethyl‐1,2‐dihydroquinolines by the reaction of anilines with acetone catalyzed by ytterbium(III) triflate [Yb(OTf)₃] in ionic liquids. The catalyst and ionic liquids can be easily recovered and reused, making this method friendly and environmentally acceptable.     

Brønsted Acidic Ionic Liquid–Catalyzed One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and Thiones Under Solvent-Free Conditions

An efficient and convenient procedure for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and thiones by condensation of ethylacetoacetate, aldehydes, and urea or thiourea in the presence of methylimidazolium hydrogensulfate is described. Aromatic and aliphatic aldehydes reacted easily to afford the corresponding 3,4-dihydropyrimidin-2(1H)-ones and thiones under solvent-free conditions. The use of nontoxic and inexpensive materials, straightforward and clean workup, short reaction times, and good yields are the advantages of this method.

Ammonium Chloride–Catalyzed One-Pot Synthesis of Tetrahydrobenzo[α]xanthen-11-one Derivatives Under Solvent-Free Conditions

A one-pot, multicomponent reaction of aldehydes, dimedone, and β-naphthols is described for the preparation of 12-aryl- or 12-alkyl-8,9,10,12-tetrahydrobenzo[α]xanthen-11-one derivatives using ammonium chloride as a mild, inexpensive, and environmentally benign catalyst under solvent-free conditions. Different types of aldehyde and β-naphthol derivatives are used in the reaction, and in all cases the products were synthesized successfully.

Reductive Amination of Aldehydes and Ketones Under Heterogeneous and Solvent-Free Conditions Using Sodium-Borohydride and Silica-Gel–Supported Sulfuric Acid

A regioselective and convenient procedure for preparation of amines by reductive amination of aldehydes and ketones using sodium borohydride in the presence of sulfuric acid supported on silica gel as an active, inexpensive, and recoverable catalyst under heterogeneous and solvent-free conditions at room temperature is described.     

Solvent-Free Synthesis of Tertiaryα-Hydroxyphosphates by the Triethylamine-Catalyzed Hydrophosphonylation of Ketones

Abstract

A new, environmentally benign, convenient, and easy method of synthesizing tertiary α-hydroxyphosphonates by the triethylamine-catalyzed hydrophosphonylation of unactivated ketones was developed. In the presence of triethylamine, aromatic or heteroaromatic ketones can react with phosphite to form tertiary α-hydroxyphosphonates under solvent-free and mild conditions. The proposed method was also suitable for functionalized ketones.